Electronic timepiece including an added partition and associated assembly method

ABSTRACT

The electronic timepiece ( 10 ) includes a case ( 12 ) that contains at least one first and one second electronic module ( 14, 16 ) powered by a battery ( 18 ). The case ( 12 ) is formed by a middle part ( 20 ), which is closed by a protective crystal ( 22 ) placed above a display device ( 24 ) and by a cover ( 26 ) added to the case ( 12 ). The case ( 12 ) includes an added partition ( 32 ), which is secured to the middle part ( 20 ) and which delimits a top compartment ( 34 ) containing the first electronic module ( 14 ) and a bottom compartment ( 36 ) containing the second electronic module ( 16 ). The battery ( 18 ) is arranged in a complementary housing arranged in the bottom face ( 40 ) of the partition ( 32 ). A method of assembling the timepiece ( 10 ) is also provided.

This application claims priority from European Patent Application No. EP06117501.4, filed Jul. 19, 2006, the entire disclosure of which isincorporated herein by reference.

FIELD OF THE INVENTION.

The invention concerns an electronic timepiece and a method for theassembly thereof.

BACKGROUND OF THE INVENTION

The invention concerns more particularly an electronic timepiececomprising a case that contains at least one first and one secondelectronic modules electrically connected to each other and powered by abattery, wherein the case is formed by a middle part that is closed, inthe top part thereof, by a protective crystal placed above a displaydevice and, in the bottom part thereof, by a cover added to the case.

US Patent No. 2005/0253047 discloses and shows a timepiece formed by awristwatch comprising time functions such as time display and auxiliaryfunctions to the time display formed by functions for measuring thepulse of the wearer of the watch. The time functions and the watchdisplay control are processed by an electronic circuit arranged on a topprinted circuit board which is secured in the middle part. The pulsemeasuring functions are processed by an electronic circuit arranged on abottom printed circuit board which is secured to the bottom of thecover.

In this type of timepiece, the assembly of the various components whichare superposed in the case is relatively complex. Securing means have tobe provided inside the case, especially adapted to a given configurationof the timepiece. When one wishes to replace one electronic module withanother electronic module, the structure of the case has to be alteredwhich raises problems of cost and flexibility in the production line.

Moreover, the securing systems that are provided in the case are notcompletely satisfactory and some components, such as the battery, arenot sufficiently held.

It has also been observed that, when the battery is changed, theelectronic modules are very exposed which can lead to deteriorationhaving a negative effect on the reliability of the timepiece.

It is an object of the invention to overcome these drawbacks byproposing a simple and economical solution.

SUMMARY OF THE INVENTION

The invention therefore proposes a timepiece of the type previouslydescribed, characterized in that the case includes an added partition orwall, which is secured to the middle part and which delimits, in the toppart of the case, a top compartment containing the first electronicmodule, and in the bottom part of the case, a bottom compartmentcontaining the second electronic module, and in that the battery isarranged in a complementary housing arranged in the bottom face of thepartition.

Owing to the invention, the two electronic modules are better insulatedfrom each other and they are better held in the case. Moreover, thebattery can be changed more easily and the arrangement thereof in thepartition housing facilitates the electric connection thereof to theelectronic modules.

Preferably, the second electronic module is formed by a printed circuitboard carrying electronic components and it is secured to the inner faceof the cover. The cover includes several studs which are integral withthe cover and which extend vertically through associated holes arrangedin the printed circuit board. The printed circuit board is heldvertically on the cover by a deformation of the free end of each stud.This arrangement of the second electronic module on the coverfacilitates both the assembly of the second electronic module in thecase and changing the battery.

Advantageously, the first electronic module includes a male connectorwhich extends downwards through an associated aperture in the partition,and the second electronic module comprises a complementary femaleconnector which extends upwards to electrically connect the twoelectronic modules. The use of these connectors simplifies the electricconnection of the second electronic module to the first electronicmodule, particularly by limiting the number of contact fixturesnecessary for this connection. A more reliable electric connection isthus obtained and the number of assembly operations is reduced.

Preferably, the first electronic module comprises a printed circuitboard that is secured to the middle part and the male connector isrigidly fixed to the bottom face of the printed circuit board. The firstelectronic module includes the display device, a watch circuit, and adisplay control circuit, and the second electronic module is dedicatedto auxiliary functions such as the pulse measuring functions. Aperfectly modular construction is thus obtained and it is possible toalter the second electronic module without altering the first electronicmodule.

According to an advantageous embodiment, the watch circuit and thedisplay control circuit are arranged on the printed circuit board. Thedisplay device and the printed circuit board are fixed to a spacerinserted between the display device and the printed circuit board toform the first electronic module. The spacer is fixed to the middlepart. Owing to this embodiment, the assembly operations are facilitated,and the first electronic module forms an assembly that is easier tohandle. Moreover, by keeping a spacer with an identical externalperipheral structure, it is possible to alter the printed circuit boardand the display device, without this requiring any alteration to thestructure of the top compartment of the case.

Preferably, the display device is secured in a removable manner to thespacer by an elastic male and female joint, which allows the elementsforming the display device to be changed more quickly and simply, whilekeeping the same spacer.

Advantageously, the bottom of the battery housing comprises holes givingaccess to test and/or programming zones of the first electronic module.Thus, the first electronic module is protected by the partition or walland it is possible to act on the first electronic module withoutdismantling the partition.

The partition extends substantially over the entire surface of themiddle part in a parallel plane to the general plane of the cover. Thecover is secured to the partition which is axially inserted between themiddle part and the cover. A “sandwich” assembly is obtained which iseasy to mass-produce and which provides good protection for the firstelectronic module when the battery is changed or one wishes to act onthe second electronic module.

The invention also proposes a method of assembling a timepiece of thetype previously described, characterized in that it comprises thefollowing successive steps:

-   -   inserting the first electronic module in the middle part,    -   fixing the partition onto the middle part,    -   mounting the battery in a housing arranged on the bottom face of        the partition,    -   fixing the cover carrying the second electronic module on the        case.

Advantageously, there is a step of securing the second electronic moduleonto the cover, which comprises the following successive steps:positioning the printed circuit board of the second electronic module onthe studs of the cover, andapplying thermo-welding to the free ends ofthe studs so as to create localised deformations retaining the printedcircuit board against the inner face of the cover.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will appear moreclearly upon reading the following detailed description, made withreference to the annexed drawings, given by way of non-limiting exampleand in which:

FIG. 1 is an exploded perspective view, which shows a preferredembodiment of an electronic timepiece according to the invention,

FIG. 2 is a view along the transverse cross-sectional plane 2-2 whichshows the timepiece of FIG. 1;

FIG. 3 is an exploded perspective view which shows a first electronicmodule fitted to the timepiece of FIG. 1;

FIG. 4 is a view along the transverse cross-sectional plane 4-4 whichpartially shows the first electronic module and the arrangement of abacklighting light emitting diode;

FIG. 5 is an exploded perspective view which shows the case of thetimepiece of FIG. 1 after it has been turned over and the firstelectronic module has been inserted and before the partition of theinvention has been mounted;

FIG. 6 is a similar perspective view to FIG. 5, which shows the caseafter the partition has been mounted and before the battery powering thetimepiece has been mounted;

FIG. 7 is a similar exploded perspective view to that of FIG. 5, whichshows the case after the battery has been installed and before the covercarrying a second electronic module has been mounted;

FIG. 8 is a flow diagram, which shows the timepiece of FIG. 1 and theelectronic modules thereof.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, an orthogonal frame of reference (whereinV, L, T respectively define the vertical V, longitudinal L andtransverse T directions) will be used in a non limiting manner. Similaror identical elements may be designated by the same references.

FIGS. 1 to 8 show the various elements forming an electronic timepiece10 made in accordance with the teaching of the invention in the form ofa wristwatch.

Timepiece 10 comprises a case 12, which contains first and secondelectronic modules 14, 16 electrically connected to each other andsupplied with electric current by a battery 18. The electronic modules14, 16 are stacked along a vertical axial direction A1.

In the following description, an axial orientation along vertical axialdirection A1 will be used in a non-limiting manner.

Case 12 is formed by an overall circular middle part 20 which is closed,in the top part thereof, by a protective crystal 22 placed above adisplay device 24 and, in the lower part thereof, by a cover 26 added tothe case 12.

Middle part 20, which extends substantially in a horizontal plane,comprises in the longitudinal end edges thereof, horns 28, 30, forattaching the strands of a wristband or bracelet (not shown) and, in thetransverse end edges thereof, push-buttons 31 for manually controllingtimepiece 10.

According to the teachings of the invention, case 12 includes an addedpartition or wall 32, which is fixed to middle part 20 and whichdelimits in the top part of case 12, a top comportment 34 containingfirst electronic module 14 and, in the bottom part of case 12, a bottomcompartment 36 containing second electronic module 16.

Battery 18 is arranged in the bottom compartment 36, between partition32 and the second electronic module 16, in a complementary housing 38arranged in the bottom face 40 of partition 32. Preferably, as shown inparticular in FIGS. 5 to 7, housing 38 is made integral with partition32, here in the form of an axial skirt 41 comprising axial notches whichfacilitate the deformation of axial skirt 41 radially outwards to allowbattery 18 to be inserted in housing 38. A securing ring 42 is fittedonto the external axial walls of axial skirt 41, after insertion ofbattery 18, so as to retain battery 18 in its housing 38. The bottom 43of housing 38 includes orifices 45, which provide access to test and/orprogramming zones of first electronic module 14.

A preferred embodiment of the first electronic module 14 is shown inmore detail in FIG. 3.

The first electronic module 14 is formed here by the assembly of adisplay device 24 with a first printed circuit board 44, an assemblyspacer 46 being axially inserted between display device 24 and printedcircuit board 44.

Spacer 46 has the shape here of an substantially rectangular frame whichis received in a complementary manner in top compartment 34 of case 12and which is secured to middle part 20. Spacer 46 comprises, in the toppart thereof, elastic hooks 48, which are provided to allow displaydevice 24 to fit elastically onto spacer 46, and it comprises, in thebottom part thereof, studs 50, which are received in complementary holes52 of the first printed circuit board 44 so as to retain first printedcircuit board 44 axially against the bottom face of spacer 46.

The display device 24 is preferably formed by a liquid crystal cell 54of generally rectangular shape arranged above a backlighting device 56.Backlighting device 56 includes here, from top to bottom, a diffusionfilter 58, a waveguide 60, a reflector filter 62 and a light emittingdiode 64, which is mounted on the top face 66 of the first printedcircuit board 44 so as to emit light beams inside waveguide 60.

According to an advantageous embodiment, illustrated by FIGS. 3 and 4,light emitting diode 64 is arranged in a corner of the first printedcircuit board 44, so that the diode is located in a corresponding cornerof spacer 46. In this corner, spacer 46 has substantially vertical wallswhich define a recess 67. Recess 67 is open downwards to allow forinserting light emitting diode 64 and it is open upwards, opposite theentry surface 69 of waveguide 60, to allow the light rays to penetratewaveguide 60.

This recess 67 forms a screen which prevents the light rays emitted bylight emitting diode 64 outside waveguide 60 from propagating insidemiddle part 20. This is particularly useful in the case where middlepart 20 is made of a translucent material.

First printed circuit board 44 comprises a clock circuit 68 and adisplay control circuit 70, which is electrically connected to liquidcrystal cell 54 via a flexible connector 72. Clock circuit 68 comprisesa time base and it is provided for calculating conventional timefunctions, such as the current time, the date, etc.

A male connector 74 is rigidly mounted on the bottom face 76 of firstprinted circuit board 44 so as to allow first electric module 14 to beelectrically connected to second electric module 16, via a complementaryfemale connector 78. All of the electric connections of secondelectronic module 16 to the first electronic module 14 and to battery 14pass through this female connector 78.

The bottom face 76 of the first printed circuit board 44 includeselectric contact studs 79 which are arranged opposite associatedorifices 45 of partition 32 and which form test and/or programming zonesof first electronic module 14. These studs 79 allow, for example, theoperation of clock circuit 68 and display control circuit 70 to betested by means of an electronic test tool (not shown).

The second electric module 16 is formed here by a second printed circuitboard 80 comprising electronic components dedicated to functionsauxiliary to the time functions.

According to the example embodiment shown in the Figures, theseauxiliary functions comprise functions linked to measuring the pulse ofthe wearer of the watch. Thus, the second printed circuit board 80includes a pulse measuring unit 82 and a pulse measurement processingunit 84 which communicates the data to be displayed to the displaycontrol circuit 70, in particular the value of the wearer's pulse.

Of course, according to variants (not shown) of the invention, theauxiliary functions could include functions other than pulsemeasurement, for example altimeter, compass, satellite positioning,telephony functions, etc.

Advantageously, the second printed circuit board 80 is fixed to theinner face 86 of cover 26. Thus cover 26 includes several studs 88,which are made integral with cover 26 and which extend verticallythrough associated holes 90 arranged in the second printed circuit board80. The second printed circuit board 80 is retained vertically againstcover 26 by a deformation of the free end of each stud 88.

The female connector 78 is rigidly mounted on the top face of the secondprinted circuit board 80 and extends vertically upwards.

According to the preferred embodiment of the invention, cover 26 issecured to the bottom face 40 of partition 32, such that partition 32 isaxially wedged between middle part 20 and cover 26. Cover 26 is fixedhereby means of four screws 91, which pass vertically through partition32 to be screwed into threaded holes 93 of middle part 20.

Partition 32 extends substantially over the entire surface of middlepart 20 in a horizontal plane, between horns 28, 30, such that partition32 covers all of the bottom face 76 of the first printed circuit board.

Partition 32 includes an aperture 92 opposite the male connector 74,which enables male connector 74 to fit into female connector 78 throughpartition 32. Advantageously, the free end 94 of the male connector 74is substantially flush vertically with the edge 96 of aperture 92, whichguarantees proper protection of male connector 74, when cover 26 and thesecond electronic module 16 are dismantled.

Advantageously, the electric connection of the first electronic module14 to battery 18 is achieved by means of two metal contact lugs 98 whichare arranged in the first compartment 34, between the first printedcircuit board 44 and the top face 100 of partition 32, and which extendpartially over the bottom 43 of battery housing 38.

Push-buttons 31 are provided with metal contact strips 102, which arearranged in first compartment 34, between the external peripheral edge104 of the first printed circuit board 44 and the inner axial wall 106of middle part 20.

It will be noted that all of the small independent electric connectingelements, such as contact lugs 98 and contact strips 102 are arranged intop compartment 34. Thus, the electric connection of the secondelectronic module 16 is simplified since all the electric connectionsthereof pass through female connector 78. Moreover, when cover 26 isdismantled, for example to change battery 18, there is no risk of losingcomponents or of contact lugs 98 and contact strips 102 being poorlypositioned.

Electronic modules 14 and 16 of timepiece 10 according to the inventionenjoy good mechanical and electric protection, in particular whenbattery 18 is being changed.

The method of assembly timepiece 10 according to the invention will nowbe described.

The first electronic module 14 is pre-assembled, by mounting displaydevice 24, backlighting device 56 and first printed circuit board 44 onspacer 46, and then the first electronic module is axially inserted inmiddle part 20. Case 12 is then in the configuration shown in FIG. 5.

Contact lugs 98 and contact strips 102 are then arranged in theirrespective positions against the first printed circuit board 44.

Next, partition 32 is axially mounted against the bottom face of middlepart 20 and fixed, for example by bonding. Partition 32 is centred, in ahorizontal plane, relative to middle part 20, for example by means ofcentring studs 108 made integral with partition 32.

Battery 18 is inserted in its housing 38 and held in position by the fitof securing ring 42, as shown in FIG. 7.

After having secured second electronic module 16 to cover 26, the coveris secured to partition 32 by means of screws 91.

Preferably, the step of securing the second electronic module 16 tocover 26 includes a positioning step during which the studs 88 of cover26 are axially inserted into corresponding holes 90 of the secondprinted circuit board 80. Holes 90 are sized so as to arranged a radialplay between each stud 88 and the inner edge of the corresponding hole90 to allow a slight clearance of the second printed circuit board 80 ina horizontal plane and thus facilitate the centring of the secondprinted circuit board 80 relative to the first printed circuit board 44which is fixed. The final centring of the second printed circuit board80 relative to first printed circuit board 44 is then determined by maleconnector 74 fitting inside female connector 78.

After this positioning step, the free end of each stud 88 is deformed byheat, which secures the second printed circuit board 80 on cover 26 bythermo-welding. At the end of the thermo-welding, the free end of eachstud 88 is flattened and forms a disc of larger diameter than thediameter of the associated hole 90.

1. An electronic timepiece including: a case that contains at leastfirst and second electronic modules electrically connected to each otherand powered by a battery, wherein the case is formed by a middle part,which is closed, in the top part thereof, by a protective crystal placedabove a display device and, in the bottom part thereof, by a cover addedto the case, wherein the case includes an added partition, which issecured to the middle part and which delimits, in the top part of thecase, a top compartment containing the first electronic module and, inthe bottom part of the case, a bottom compartment containing the secondelectronic module, and wherein the battery is arranged in acomplementary housing arranged in the bottom face of the partition. 2.The timepiece according to claim 1, wherein the second electronic moduleis secured to the inner face of the cover.
 3. The timepiece according toclaim 2, wherein the second electronic module is formed by a printedcircuit board carrying electronic components, and wherein the coverincludes several studs, which are made integral with the cover and whichextend vertically through associated holes arranged in the printedcircuit board, and wherein the printed circuit board is retainedvertically on the cover by a deformation of a free end of each stud. 4.The timepiece according to claim 1, wherein the first electronic moduleis secured to the middle part.
 5. The timepiece according to claim 1,wherein the first electronic module includes a male connector thatextends downwards through an associated aperture of the partition, andwherein the second electronic module includes a complementary femaleconnector that extends upwards for the electric connection of the twoelectronic modules.
 6. The timepiece according to claim 5, wherein thefirst electronic module includes a printed circuit board and wherein themale connector is rigidly connected to the bottom face of the printedcircuit board.
 7. The timepiece according to claim 1, wherein the firstelectronic module includes the display device, a clock circuit and adisplay control circuit, and wherein the second electronic module isdedicated to auxiliary functions to the time functions.
 8. The timepieceaccording to claim 7, wherein the clock circuit and the display controlcircuit are arranged on a printed circuit board, wherein the displaydevice and the printed circuit board are secured to a spacer insertedbetween the display device and the printed circuit board to form thefirst electronic module, and wherein the spacer is secured to the middlepart.
 9. The timepiece according to claim 8, wherein the display deviceis removably secured to the spacer by an elastic male and female joint.10. The timepiece according to claim 1, wherein the portion of the addedpartition forming the bottom of the housing of the battery comprisesholes formed therein for providing access to test zones, or programmingzones, or test zones and programming zones, of the first electronicmodule.
 11. The timepiece according to claim 1, wherein the partitionextends substantially over the entire surface of the middle part in aparallel plane to a general plane of the cover.
 12. The timepieceaccording to claim 11, wherein the cover is secured to the partition,the partition being inserted between the middle part and the cover. 13.A method of assembling a timepiece according to claim 1, wherein themethod includes the following successive steps: (a) inserting the firstelectronic module in the middle part; (b) securing the partition to themiddle part; (c) mounting the battery in the housing arranged on thebottom face of the partition; and, (d) securing the cover carrying thesecond electronic module on the case.
 14. A method of assembling atimepiece according to claim 3, wherein the method includes thefollowing successive steps: (a) inserting the first electronic module inthe middle part; (b) securing the partition to the middle part; (c)mounting the battery in the housing arranged on the bottom face of thepartition; and (d) securing the cover carrying the second electronicmodule on the case, wherein the method further includes a step of (e)securing the second electronic module to the cover and the followingsuccessive steps of: (f) positioning the printed circuit board of thesecond electronic module on the studs of the cover; and (g) applyingthermo-welding to the free ends of the studs so as to create localiseddeformations retaining the printed circuit board against the inner faceof the cover.
 15. The timepiece according to claim 2, wherein the firstelectronic module includes a male connector that extends downwardsthrough an associated aperture of the partition, and wherein the secondelectronic module includes a complementary female connector that extendsupwards for the electric connection of the two electronic modules. 16.The timepiece according to claim 3, wherein the first electronic moduleincludes a male connector that extends downwards through an associatedaperture of the partition, and wherein the second electronic moduleincludes a complementary female connector that extends upwards for theelectric connection of the two electronic modules.
 17. The timepieceaccording to claim 4, wherein the first electronic module includes amale connector that extends downwards through an associated aperture ofthe partition, and wherein the second electronic module includes acomplementary female connector that extends upwards for the electricconnection of the two electronic modules.
 18. The timepiece according toclaim 7, wherein the auxiliary functions include time pulse functions.